JP2001096395A - Method of manufacturing wire solder containing flux from solder hard to machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a wire solder containing flux from solder hard to machine such as lead-free solder. SOLUTION: A flux-containing wire solder is manufactured from solder hard to machine by forming a long and thin plate solder having a groove to add the flux in the longitudinal direction and adding the flux into its groove.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing flux-cored wire solder from hard-to-work solder such as lead-free solder to which bismuth is added.

[0002]

2. Description of the Related Art Conventionally, tin-lead solder has been mainly used for soldering. However, in recent years, the elution of lead from the waste of automobiles and home appliances has become a major environmental problem.
Therefore, the need for lead-free soldering has been increasing.

[0003] Solders to which silver, bismuth, etc. are added as an alternative element to lead have already been developed by solder manufacturers, and the material development itself has progressed considerably. It is.

[0004] One of the causes is that the solder containing silver becomes expensive and the solder containing a large amount of bismuth has poor workability (hard workability).

On the other hand, a flux-cored wire solder having a built-in flux is often used for soldering related to a semiconductor.

As shown in FIG. 1, this flux-containing solder is manufactured by continuous casting or ordinary ingot from an ordinary lead-tin solder which is not difficult to process, and is used to produce an ingot of about 50φ. And divide it into two,
The flux was introduced into the center from the flux introduction tube, pressed with an extrusion cylinder and combined to form a rod solder (original wire solder) of about 9φ or 12φ, and the diameter was reduced by a wire drawing machine.

[0007] The ordinary lead-tin solder is very soft and can be easily split or crimped, so that the flux-cored wire solder can be manufactured as described above. However, hard and brittle lead-free solder (hard-to-work solder) containing 3% by weight or more of bismuth has poor workability, and cannot be processed into flux-cored wire solder by the above-mentioned conventional method. Was.

Conventionally, as shown in FIG. 2, a difficult-to-work solder is manufactured by manufacturing a solder ingot or manufacturing a solder slab by continuous casting, and extruding the solder slab into a linear shape with a piston. Processed into solder.

The above method has a problem that not only the productivity is extremely poor because the extrusion speed is as low as 3 mm / min, but also it is not possible to use a flux-containing solder having a built-in flux in the solder.

[0010]

SUMMARY OF THE INVENTION The present invention relates to a method of manufacturing a flux-cored wire solder from a difficult-to-work solder such as a lead-free solder containing a large amount of bismuth. The purpose is to provide.

[0011]

According to the present invention, there is provided an elongated thin sheet solder having a groove for introducing a flux in a longitudinal direction from a difficult-to-process solder, and the flux is inserted into the groove. The opening of the groove is closed.

[0012] The elongated thin sheet solder having the groove for entering the flux in the length direction is formed, for example, from a difficult-to-work solder into a thin sheet solder provided with a number of grooves for entering the flux, and cutting the thin sheet solder into strips. Easily obtained by:

A flux-cored solder cannot be made from an ingot of a hard-to-work solder material by extrusion or drawing. The present invention is formed from a difficult-to-work solder into an elongated thin plate with a groove, filling the groove with a flux,
The gist of the present invention is that a flux-cored wire solder is successfully obtained by wire drawing.

[0014]

Next, an embodiment of the present invention will be described.

FIG. 3 shows an outline of the manufacturing process of the present invention, and a solder thin plate 2 in which a number of grooves 1 for inserting flux are arranged in parallel from a difficult-to-work solder is manufactured. A narrow acute angle groove 3 for cutting is formed between adjacent grooves 1. If a cutting groove is formed on the back surface opposite to the groove 3, the separation is further facilitated.

The thickness of the solder thin plate 2 is preferably about 1 to 3 mm, and if it is too thick, it becomes difficult to draw.

Then, the groove 3 is cut into an elongated thin plate (strip shape) with a cutter. The width of the elongated thin plate solder 4 is preferably set to about 1 to 3 mm for ease of drawing. If the elongated thin plate solder 4 is formed with the groove 3 so as to have a substantially semicircular cross section, a circular flux-cored wire solder can be easily formed by wire drawing.

Next, the groove 1 is filled with a flux (dust) 5, and a flux-containing solder 6 is drawn by wire drawing.
And

The method of manufacturing the solder thin plate 2 from hard-to-work solder is not particularly limited. Although a molding method such as a rolling method and a casting method may be used, a continuous casting method (OC
C process, Ohno type continuous casting method) should be used.

The OCC process differs from ordinary continuous casting in that the temperature is around the solidification temperature (for example, 10 to 30 degrees below the solidification temperature).
This is a method of continuously obtaining a cast piece using a heating mold heated to about (° C. high temperature). According to this method, a unidirectionally solidified structure and / or a single crystal cast piece can be produced. Usually, a cast piece in which a unidirectionally solidified structure and a single crystal are continuously provided is obtained.

The unidirectionally solidified structure and the single crystal obtained by the OCC process are very soft and rich in workability because each macrocrystal is considerably large. for that reason,
Whether the material is a difficult-to-work material or by a drawing method,
A flux-cored wire solder can be easily formed.

In addition, since this OCC process does not basically solidify in the mold, there is no friction between the slab and the mold surface. The manufacture of the pieces is relatively easy.

The flux 5 can be injected into the groove 1 by using an injector or the like. The wire drawing process may be performed by a normal wire drawing method while narrowing the upper side of the groove 1 to close the opening and enclosing the flux, narrowing the cross section, and processing the wire into a wire solder containing a flux at the center.

In the above embodiment, the elongated thin plate solder 4 is
Although it is formed from the solder thin plate 2 provided with a large number of grooves, this is not always necessary, and may be formed directly by, for example, a molding method.

The hard-to-work solder used in the present invention is a material which is impossible or extremely difficult to form a wire solder by drawing, extruding, rolling or the like.

Examples of such a material include solder having a tensile strength of 60 N / mm ² or more and / or an elongation of 30% or less.

Examples of such hard-to-work solder include lead-free solder containing 3% by weight or more of bismuth. Table 1 below shows specific examples of such hard-to-work solder.

[0028]

[Table 1]

In the above embodiment, since the thin plate 2 is formed first, the thin plate 2 can be formed without difficulty even from a hard-to-work material solder which is difficult to form on a wire.

Although it is possible to cast the thin plate 2 into the elongated thin plate solder 4, it is preferable to cut the thin plate 2 into the elongated thin plate solder 4 because the productivity is improved and the cost is reduced.

In the above-described embodiment, the thin plate 2 with the groove 1 is cast in one step. This is because forming the groove 1 later becomes extremely difficult. By doing so, the number of steps can of course be reduced.

According to the present invention, a thin sheet solder having an elongated groove is formed, and after flux is put into the groove, the opening of the groove is closed, or the opening of the groove is closed, and the wire is drawn. , A flux-cored wire solder can be formed. Heretofore, it has not been possible to form flux-cored wire solder from hard-to-work solder.

[0033]

According to the present invention, a flux-cored wire solder can be easily manufactured from hard-to-work solder which has been impossible or extremely difficult to manufacture conventionally.

Further, according to the present invention, the flux-cored wire solder can be manufactured from inexpensive lead-free solder containing bismuth, so that the problem of lead toxicity is avoided and the contribution to environmental problems is extremely large. .

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view for manufacturing a conventional solder wire with a dent.

FIG. 2 is a schematic cross-sectional view of manufacturing a linear solder from a conventional hard-to-work solder.

FIG. 3 is a schematic view illustrating a manufacturing process of the present invention.

[Explanation of symbols]

 1 Flux filling groove 2 Solder thin plate 3 Cutting groove 4 Slender thin plate (strip-like) solder 5 Flux

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // B23K 35/26 310 B23K 35/26 310A

Claims (8)

[Claims] 1. A hard-to-work solder which is characterized by forming an elongated thin plate solder having a groove for introducing flux in the longitudinal direction from the hard-to-work solder, filling the groove with the flux, and closing the opening of the groove. For manufacturing flux-cored wire solder. 2. A thin sheet solder having a plurality of grooves for introducing flux from said difficult-to-process solder is formed on said sheet solder, and said thin sheet solder is cut to form an elongated thin sheet solder having grooves for entering flux in said length direction. Claim 1 to form
The production method described in 1. 3. The method according to claim 1, wherein the wire drawing is performed after closing the opening of the groove or while closing the opening of the groove. 4. The manufacturing method according to claim 2, wherein a groove for cutting is formed between adjacent grooves for entering said flux. 5. The method according to claim 1, wherein said hard-to-work solder has a tensile strength of 60 N /.
mm ² or more and / or 30% or less of elongation.
5. The production method according to any one of 4. 6. A thin and long sheet solder having a width of 1 to 3 mm,
The manufacturing method according to any one of claims 1 to 5, wherein the height is 1 to 3 mm. 7. The thin sheet solder has a directionally solidified structure and / or
Or the manufacturing method of any one of Claims 1-6 which consists of a single crystal. 8. The manufacturing method according to claim 7, wherein said thin sheet solder is formed by a continuous casting method using a heating mold.